dma-mapping: fix dma_addressing_limited if dma_range_map is scanned

  After scanning the dma_range_map, if it is found that not all of the
system RAM ranges are encompassed within it, an incorrect calculation
occurs for dma_addressing_limited(), which prevents the nvme device
dma mapping in the checking path of phys_to_dma().

E.g. On an Armv8 Ampere server, the dsdt ACPI table is:
 Method (_DMA, 0, Serialized)  // _DMA: Direct Memory Access
            {
                Name (RBUF, ResourceTemplate ()
                {
                    QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
                        0x0000000000000000, // Granularity
                        0x0000000000000000, // Range Minimum
                        0x00000000FFFFFFFF, // Range Maximum
                        0x0000000000000000, // Translation Offset
                        0x0000000100000000, // Length
                        ,, , AddressRangeMemory, TypeStatic)
                    QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
                        0x0000000000000000, // Granularity
                        0x0000006010200000, // Range Minimum
                        0x000000602FFFFFFF, // Range Maximum
                        0x0000000000000000, // Translation Offset
                        0x000000001FE00000, // Length
                        ,, , AddressRangeMemory, TypeStatic)
                    QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
                        0x0000000000000000, // Granularity
                        0x00000060F0000000, // Range Minimum
                        0x00000060FFFFFFFF, // Range Maximum
                        0x0000000000000000, // Translation Offset
                        0x0000000010000000, // Length
                        ,, , AddressRangeMemory, TypeStatic)
                    QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
                        0x0000000000000000, // Granularity
                        0x0000007000000000, // Range Minimum
                        0x000003FFFFFFFFFF, // Range Maximum
                        0x0000000000000000, // Translation Offset
                        0x0000039000000000, // Length
                        ,, , AddressRangeMemory, TypeStatic)
                })

But the System RAM ranges are:
cat /proc/iomem |grep -i ram
90000000-91ffffff : System RAM
92900000-fffbffff : System RAM
880000000-fffffffff : System RAM
8800000000-bff5990fff : System RAM
bff59d0000-bff5a4ffff : System RAM
bff8000000-bfffffffff : System RAM
So some RAM ranges are out of dma_range_map.

Fixes it by checking whether each of the system RAM resources can be
properly encompassed within the dma_range_map.

Signed-off-by: Jia He <justin.he@arm.com>
---
 include/linux/dma-mapping.h |  8 +++++--
 kernel/dma/mapping.c        | 45 +++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 2 deletions(-)
  

On 12/09/2023 9:40 am, Jia He wrote:
> After scanning the dma_range_map, if it is found that not all of the
> system RAM ranges are encompassed within it, an incorrect calculation
> occurs for dma_addressing_limited(), which prevents the nvme device
> dma mapping in the checking path of phys_to_dma().

Nit: the subject and this description aren't very clear - the key point 
here is the unusual case that the range map covers right up to the top 
of system RAM, but leaves a hole somewhere lower down. There's no issue 
with the more typical case where some RAM exists above the top of the 
range map, since bus_dma_limit will capture that and work as expected.

> E.g. On an Armv8 Ampere server, the dsdt ACPI table is:
>   Method (_DMA, 0, Serialized)  // _DMA: Direct Memory Access
>              {
>                  Name (RBUF, ResourceTemplate ()
>                  {
>                      QWordMemory (ResourceConsumer, PosDecode, MinFixed,
> MaxFixed, Cacheable, ReadWrite,
>                          0x0000000000000000, // Granularity
>                          0x0000000000000000, // Range Minimum
>                          0x00000000FFFFFFFF, // Range Maximum
>                          0x0000000000000000, // Translation Offset
>                          0x0000000100000000, // Length
>                          ,, , AddressRangeMemory, TypeStatic)
>                      QWordMemory (ResourceConsumer, PosDecode, MinFixed,
> MaxFixed, Cacheable, ReadWrite,
>                          0x0000000000000000, // Granularity
>                          0x0000006010200000, // Range Minimum
>                          0x000000602FFFFFFF, // Range Maximum
>                          0x0000000000000000, // Translation Offset
>                          0x000000001FE00000, // Length
>                          ,, , AddressRangeMemory, TypeStatic)
>                      QWordMemory (ResourceConsumer, PosDecode, MinFixed,
> MaxFixed, Cacheable, ReadWrite,
>                          0x0000000000000000, // Granularity
>                          0x00000060F0000000, // Range Minimum
>                          0x00000060FFFFFFFF, // Range Maximum
>                          0x0000000000000000, // Translation Offset
>                          0x0000000010000000, // Length
>                          ,, , AddressRangeMemory, TypeStatic)
>                      QWordMemory (ResourceConsumer, PosDecode, MinFixed,
> MaxFixed, Cacheable, ReadWrite,
>                          0x0000000000000000, // Granularity
>                          0x0000007000000000, // Range Minimum
>                          0x000003FFFFFFFFFF, // Range Maximum
>                          0x0000000000000000, // Translation Offset
>                          0x0000039000000000, // Length
>                          ,, , AddressRangeMemory, TypeStatic)
>                  })
> 
> But the System RAM ranges are:
> cat /proc/iomem |grep -i ram
> 90000000-91ffffff : System RAM
> 92900000-fffbffff : System RAM
> 880000000-fffffffff : System RAM
> 8800000000-bff5990fff : System RAM
> bff59d0000-bff5a4ffff : System RAM
> bff8000000-bfffffffff : System RAM
> So some RAM ranges are out of dma_range_map.
> 
> Fixes it by checking whether each of the system RAM resources can be
> properly encompassed within the dma_range_map.
> 
> Signed-off-by: Jia He <justin.he@arm.com>
> ---
>   include/linux/dma-mapping.h |  8 +++++--
>   kernel/dma/mapping.c        | 45 +++++++++++++++++++++++++++++++++++++
>   2 files changed, 51 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index f0ccca16a0ac..d9d1c67c8579 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -144,6 +144,7 @@ bool dma_pci_p2pdma_supported(struct device *dev);
>   int dma_set_mask(struct device *dev, u64 mask);
>   int dma_set_coherent_mask(struct device *dev, u64 mask);
>   u64 dma_get_required_mask(struct device *dev);
> +bool all_ram_in_dma_range_map(struct device *dev);
>   size_t dma_max_mapping_size(struct device *dev);
>   size_t dma_opt_mapping_size(struct device *dev);
>   bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
> @@ -475,8 +476,11 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
>    */
>   static inline bool dma_addressing_limited(struct device *dev)
>   {
> -	return min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
> -			    dma_get_required_mask(dev);
> +	if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
> +						dma_get_required_mask(dev))

Nit: indentation

> +		return true;
> +
> +	return !all_ram_in_dma_range_map(dev);
>   }
>   
>   static inline unsigned int dma_get_max_seg_size(struct device *dev)
> diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
> index e323ca48f7f2..ab407deb81b8 100644
> --- a/kernel/dma/mapping.c
> +++ b/kernel/dma/mapping.c
> @@ -14,6 +14,7 @@
>   #include <linux/of_device.h>
>   #include <linux/slab.h>
>   #include <linux/vmalloc.h>
> +#include <linux/dma-direct.h>

Nit: please keep the includes sorted alphabetically, however I do wonder 
whether this whole thing shouldn't belong in dma-direct anyway.

>   #include "debug.h"
>   #include "direct.h"
>   
> @@ -819,6 +820,50 @@ size_t dma_opt_mapping_size(struct device *dev)
>   }
>   EXPORT_SYMBOL_GPL(dma_opt_mapping_size);
>   
> +/*
> + * To check whether all ram resource ranges are mapped in dma range map
> + * Returns 0 when continuous check is needed
> + * Returns 1 if there is some ram range can't be mapped to dma_range_map
> + */
> +static int check_ram_in_range_map(unsigned long start_pfn,
> +				  unsigned long nr_pages, void *data)
> +{
> +	phys_addr_t end_paddr = (start_pfn + nr_pages) << PAGE_SHIFT;

This could still wrap to 0 on 32-bit. I think the robust thing to do is 
either spray some extra -1s and +1s around to make all the "end" values 
inclusive limits, or maybe just do everything in units of pages rather 
than bytes (i.e. use PFN_DOWN() on the bus_dma_region entry values).

> +	phys_addr_t start_paddr = start_pfn << PAGE_SHIFT;
> +	struct device *dev = (struct device *)data;
> +	struct bus_dma_region *region = NULL;
> +	const struct bus_dma_region *m;
> +
> +	while (start_paddr < end_paddr) {
> +		// find region containing start_paddr

Nit: inconsistent comment style (although it's not a particularly 
valuable comment anyway, IMO the loop itself is clear enough).

Thanks,
Robin.

> +		for (m = dev->dma_range_map; m->size; m++) {
> +			if (start_paddr >= m->cpu_start
> +			    && start_paddr - m->cpu_start < m->size) {
> +				region = (struct bus_dma_region *)m;
> +				break;
> +			}
> +		}
> +		if (!region)
> +			return 1;
> +
> +		start_paddr = region->cpu_start + region->size;
> +		/* handle overflow of phys_addr_t */
> +		if (start_paddr == 0)
> +			break;
> +	}
> +
> +	return 0;
> +}
> +
> +bool all_ram_in_dma_range_map(struct device *dev)
> +{
> +	if (!dev->dma_range_map)
> +		return 1;
> +
> +	return !walk_system_ram_range(0, ULONG_MAX, dev, check_ram_in_range_map);
> +}
> +EXPORT_SYMBOL_GPL(all_ram_in_dma_range_map);
> +
>   bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
>   {
>   	const struct dma_map_ops *ops = get_dma_ops(dev);
  

Hi Jia,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.6-rc1 next-20230912]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jia-He/dma-mapping-fix-dma_addressing_limited-if-dma_range_map-is-scanned/20230912-164126
base:   linus/master
patch link:    https://lore.kernel.org/r/20230912084002.2168-1-justin.he%40arm.com
patch subject: [PATCH] dma-mapping: fix dma_addressing_limited if dma_range_map is scanned
config: um-allyesconfig (https://download.01.org/0day-ci/archive/20230913/202309130234.COIfUg9W-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230913/202309130234.COIfUg9W-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309130234.COIfUg9W-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from init/main.c:21:
   In file included from include/linux/syscalls.h:90:
   In file included from include/trace/syscall.h:7:
   In file included from include/linux/trace_events.h:9:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from init/main.c:21:
   In file included from include/linux/syscalls.h:90:
   In file included from include/trace/syscall.h:7:
   In file included from include/linux/trace_events.h:9:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from init/main.c:21:
   In file included from include/linux/syscalls.h:90:
   In file included from include/trace/syscall.h:7:
   In file included from include/linux/trace_events.h:9:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   In file included from init/main.c:102:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
>> include/linux/dma-mapping.h:483:10: error: implicit declaration of function 'all_ram_in_dma_range_map' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           return !all_ram_in_dma_range_map(dev);
                   ^
   12 warnings and 1 error generated.
--
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
>> include/linux/dma-mapping.h:483:10: error: implicit declaration of function 'all_ram_in_dma_range_map' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           return !all_ram_in_dma_range_map(dev);
                   ^
   arch/um/os-Linux/drivers/ethertap_kern.c:66:5: warning: no previous prototype for function 'ethertap_setup' [-Wmissing-prototypes]
   int ethertap_setup(char *str, char **mac_out, void *data)
       ^
   arch/um/os-Linux/drivers/ethertap_kern.c:66:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int ethertap_setup(char *str, char **mac_out, void *data)
   ^
   static 
   13 warnings and 1 error generated.
--
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
>> include/linux/dma-mapping.h:483:10: error: implicit declaration of function 'all_ram_in_dma_range_map' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           return !all_ram_in_dma_range_map(dev);
                   ^
   arch/um/os-Linux/drivers/tuntap_kern.c:56:5: warning: no previous prototype for function 'tuntap_setup' [-Wmissing-prototypes]
   int tuntap_setup(char *str, char **mac_out, void *data)
       ^
   arch/um/os-Linux/drivers/tuntap_kern.c:56:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int tuntap_setup(char *str, char **mac_out, void *data)
   ^
   static 
   13 warnings and 1 error generated.
--
   In file included from net/ipv4/route.c:67:
   In file included from include/linux/memblock.h:13:
   In file included from arch/um/include/asm/dma.h:5:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from net/ipv4/route.c:67:
   In file included from include/linux/memblock.h:13:
   In file included from arch/um/include/asm/dma.h:5:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from net/ipv4/route.c:67:
   In file included from include/linux/memblock.h:13:
   In file included from arch/um/include/asm/dma.h:5:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   In file included from net/ipv4/route.c:71:
   In file included from include/linux/inet.h:42:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
>> include/linux/dma-mapping.h:483:10: error: implicit declaration of function 'all_ram_in_dma_range_map' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           return !all_ram_in_dma_range_map(dev);
                   ^
   net/ipv4/route.c:880:6: warning: variable 'log_martians' set but not used [-Wunused-but-set-variable]
           int log_martians;
               ^
   13 warnings and 1 error generated.
..


vim +/all_ram_in_dma_range_map +483 include/linux/dma-mapping.h

   468	
   469	/**
   470	 * dma_addressing_limited - return if the device is addressing limited
   471	 * @dev:	device to check
   472	 *
   473	 * Return %true if the devices DMA mask is too small to address all memory in
   474	 * the system, else %false.  Lack of addressing bits is the prime reason for
   475	 * bounce buffering, but might not be the only one.
   476	 */
   477	static inline bool dma_addressing_limited(struct device *dev)
   478	{
   479		if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
   480							dma_get_required_mask(dev))
   481			return true;
   482	
 > 483		return !all_ram_in_dma_range_map(dev);
   484	}
   485
  

Hi Jia,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on hch-configfs/for-next v6.6-rc1 next-20230912]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jia-He/dma-mapping-fix-dma_addressing_limited-if-dma_range_map-is-scanned/20230912-164126
base:   linus/master
patch link:    https://lore.kernel.org/r/20230912084002.2168-1-justin.he%40arm.com
patch subject: [PATCH] dma-mapping: fix dma_addressing_limited if dma_range_map is scanned
config: um-randconfig-r012-20230912 (https://download.01.org/0day-ci/archive/20230913/202309130345.xV6bouV1-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230913/202309130345.xV6bouV1-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309130345.xV6bouV1-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from block/blk-settings.c:8:
   In file included from include/linux/bio.h:10:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from block/blk-settings.c:8:
   In file included from include/linux/bio.h:10:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from block/blk-settings.c:8:
   In file included from include/linux/bio.h:10:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     692 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     700 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     708 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     717 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     726 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     735 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   In file included from block/blk-settings.c:16:
>> include/linux/dma-mapping.h:483:10: error: call to undeclared function 'all_ram_in_dma_range_map'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     483 |         return !all_ram_in_dma_range_map(dev);
         |                 ^
   12 warnings and 1 error generated.
--
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     692 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     700 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     708 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     717 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     726 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     735 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
>> include/linux/dma-mapping.h:483:10: error: call to undeclared function 'all_ram_in_dma_range_map'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     483 |         return !all_ram_in_dma_range_map(dev);
         |                 ^
   arch/um/os-Linux/drivers/tuntap_kern.c:56:5: warning: no previous prototype for function 'tuntap_setup' [-Wmissing-prototypes]
      56 | int tuntap_setup(char *str, char **mac_out, void *data)
         |     ^
   arch/um/os-Linux/drivers/tuntap_kern.c:56:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
      56 | int tuntap_setup(char *str, char **mac_out, void *data)
         | ^
         | static 
   13 warnings and 1 error generated.
--
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     692 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     700 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     708 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     717 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     726 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     735 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
>> include/linux/dma-mapping.h:483:10: error: call to undeclared function 'all_ram_in_dma_range_map'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     483 |         return !all_ram_in_dma_range_map(dev);
         |                 ^
   arch/um/os-Linux/drivers/ethertap_kern.c:66:5: warning: no previous prototype for function 'ethertap_setup' [-Wmissing-prototypes]
      66 | int ethertap_setup(char *str, char **mac_out, void *data)
         |     ^
   arch/um/os-Linux/drivers/ethertap_kern.c:66:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
      66 | int ethertap_setup(char *str, char **mac_out, void *data)
         | ^
         | static 
   13 warnings and 1 error generated.
--
   In file included from net/ipv4/igmp.c:79:
   In file included from include/linux/inet.h:42:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from net/ipv4/igmp.c:79:
   In file included from include/linux/inet.h:42:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from net/ipv4/igmp.c:79:
   In file included from include/linux/inet.h:42:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:17:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     692 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     700 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     708 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     717 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     726 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     735 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   In file included from net/ipv4/igmp.c:79:
   In file included from include/linux/inet.h:42:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
>> include/linux/dma-mapping.h:483:10: error: call to undeclared function 'all_ram_in_dma_range_map'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     483 |         return !all_ram_in_dma_range_map(dev);
         |                 ^
   net/ipv4/igmp.c:1913:6: warning: variable 'changerec' set but not used [-Wunused-but-set-variable]
    1913 |         int     changerec = 0;
         |                 ^
   13 warnings and 1 error generated.
..


vim +/all_ram_in_dma_range_map +483 include/linux/dma-mapping.h

   468	
   469	/**
   470	 * dma_addressing_limited - return if the device is addressing limited
   471	 * @dev:	device to check
   472	 *
   473	 * Return %true if the devices DMA mask is too small to address all memory in
   474	 * the system, else %false.  Lack of addressing bits is the prime reason for
   475	 * bounce buffering, but might not be the only one.
   476	 */
   477	static inline bool dma_addressing_limited(struct device *dev)
   478	{
   479		if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
   480							dma_get_required_mask(dev))
   481			return true;
   482	
 > 483		return !all_ram_in_dma_range_map(dev);
   484	}
   485
  

> -----Original Message-----
> From: kernel test robot <lkp@intel.com>
> Sent: Wednesday, September 13, 2023 2:28 AM
> To: Justin He <Justin.He@arm.com>; Christoph Hellwig <hch@lst.de>; Marek
> Szyprowski <m.szyprowski@samsung.com>; Robin Murphy
> <Robin.Murphy@arm.com>; iommu@lists.linux.dev
> Cc: llvm@lists.linux.dev; oe-kbuild-all@lists.linux.dev;
> linux-kernel@vger.kernel.org; Justin He <Justin.He@arm.com>
> Subject: Re: [PATCH] dma-mapping: fix dma_addressing_limited if
> dma_range_map is scanned
> 
> Hi Jia,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v6.6-rc1 next-20230912] [If your patch is applied to
> the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:
> https://github.com/intel-lab-lkp/linux/commits/Jia-He/dma-mapping-fix-dma_
> addressing_limited-if-dma_range_map-is-scanned/20230912-164126
> base:   linus/master
> patch link:
> https://lore.kernel.org/r/20230912084002.2168-1-justin.he%40arm.com
> patch subject: [PATCH] dma-mapping: fix dma_addressing_limited if
> dma_range_map is scanned
> config: um-allyesconfig
> (https://download.01.org/0day-ci/archive/20230913/202309130234.COIfUg9
> W-lkp@intel.com/config)
> compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git
> f28c006a5895fc0e329fe15fead81e37457cb1d1)
> reproduce (this is a W=1 build):
> (https://download.01.org/0day-ci/archive/20230913/202309130234.COIfUg9
> W-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes:
> | https://lore.kernel.org/oe-kbuild-all/202309130234.COIfUg9W-lkp@intel.
> | com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from init/main.c:21:
>    In file included from include/linux/syscalls.h:90:
>    In file included from include/trace/syscall.h:7:
>    In file included from include/linux/trace_events.h:9:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from init/main.c:21:
>    In file included from include/linux/syscalls.h:90:
>    In file included from include/trace/syscall.h:7:
>    In file included from include/linux/trace_events.h:9:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from init/main.c:21:
>    In file included from include/linux/syscalls.h:90:
>    In file included from include/trace/syscall.h:7:
>    In file included from include/linux/trace_events.h:9:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from init/main.c:102:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
Seems I need to define a stub when DMA Kconfig is disabled.
Thanks

--
Cheers,
Justin (Jia He)

>                    ^
>    12 warnings and 1 error generated.
> --
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from arch/um/os-Linux/drivers/ethertap_kern.c:10:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
>                    ^
>    arch/um/os-Linux/drivers/ethertap_kern.c:66:5: warning: no previous
> prototype for function 'ethertap_setup' [-Wmissing-prototypes]
>    int ethertap_setup(char *str, char **mac_out, void *data)
>        ^
>    arch/um/os-Linux/drivers/ethertap_kern.c:66:1: note: declare 'static' if the
> function is not intended to be used outside of this translation unit
>    int ethertap_setup(char *str, char **mac_out, void *data)
>    ^
>    static
>    13 warnings and 1 error generated.
> --
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:17:
>    In file included from include/linux/bvec.h:10:
>    In file included from include/linux/highmem.h:12:
>    In file included from include/linux/hardirq.h:11:
>    In file included from arch/um/include/asm/hardirq.h:5:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from arch/um/os-Linux/drivers/tuntap_kern.c:6:
>    In file included from include/linux/netdevice.h:38:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
>                    ^
>    arch/um/os-Linux/drivers/tuntap_kern.c:56:5: warning: no previous
> prototype for function 'tuntap_setup' [-Wmissing-prototypes]
>    int tuntap_setup(char *str, char **mac_out, void *data)
>        ^
>    arch/um/os-Linux/drivers/tuntap_kern.c:56:1: note: declare 'static' if the
> function is not intended to be used outside of this translation unit
>    int tuntap_setup(char *str, char **mac_out, void *data)
>    ^
>    static
>    13 warnings and 1 error generated.
> --
>    In file included from net/ipv4/route.c:67:
>    In file included from include/linux/memblock.h:13:
>    In file included from arch/um/include/asm/dma.h:5:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:560:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from
> macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from net/ipv4/route.c:67:
>    In file included from include/linux/memblock.h:13:
>    In file included from arch/um/include/asm/dma.h:5:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:573:61: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE +
> addr));
> 
> ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from
> macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from net/ipv4/route.c:67:
>    In file included from include/linux/memblock.h:13:
>    In file included from arch/um/include/asm/dma.h:5:
>    In file included from arch/um/include/asm/io.h:24:
>    include/asm-generic/io.h:584:33: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^
>    include/asm-generic/io.h:594:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:604:59: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE +
> addr);
>                                                          ~~~~~~~~~~
> ^
>    include/asm-generic/io.h:692:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsb(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:700:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsw(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:708:20: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            readsl(PCI_IOBASE + addr, buffer, count);
>                   ~~~~~~~~~~ ^
>    include/asm-generic/io.h:717:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesb(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:726:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesw(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    include/asm-generic/io.h:735:21: warning: performing pointer arithmetic
> on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            writesl(PCI_IOBASE + addr, buffer, count);
>                    ~~~~~~~~~~ ^
>    In file included from net/ipv4/route.c:71:
>    In file included from include/linux/inet.h:42:
>    In file included from include/net/net_namespace.h:43:
>    In file included from include/linux/skbuff.h:28:
> >> include/linux/dma-mapping.h:483:10: error: implicit declaration of
> >> function 'all_ram_in_dma_range_map' is invalid in C99
> >> [-Werror,-Wimplicit-function-declaration]
>            return !all_ram_in_dma_range_map(dev);
>                    ^
>    net/ipv4/route.c:880:6: warning: variable 'log_martians' set but not used
> [-Wunused-but-set-variable]
>            int log_martians;
>                ^
>    13 warnings and 1 error generated.
> ..
> 
> 
> vim +/all_ram_in_dma_range_map +483 include/linux/dma-mapping.h
> 
>    468
>    469	/**
>    470	 * dma_addressing_limited - return if the device is addressing
> limited
>    471	 * @dev:	device to check
>    472	 *
>    473	 * Return %true if the devices DMA mask is too small to address all
> memory in
>    474	 * the system, else %false.  Lack of addressing bits is the prime
> reason for
>    475	 * bounce buffering, but might not be the only one.
>    476	 */
>    477	static inline bool dma_addressing_limited(struct device *dev)
>    478	{
>    479		if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
>    480							dma_get_required_mask(dev))
>    481			return true;
>    482
>  > 483		return !all_ram_in_dma_range_map(dev);
>    484	}
>    485
> 
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
  

Hi Robin,

> -----Original Message-----
> From: Robin Murphy <robin.murphy@arm.com>
> Sent: Tuesday, September 12, 2023 7:57 PM
> To: Justin He <Justin.He@arm.com>; Christoph Hellwig <hch@lst.de>; Marek
> Szyprowski <m.szyprowski@samsung.com>; iommu@lists.linux.dev
> Cc: linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] dma-mapping: fix dma_addressing_limited if
> dma_range_map is scanned
> 
> On 12/09/2023 9:40 am, Jia He wrote:
> > After scanning the dma_range_map, if it is found that not all of the
> > system RAM ranges are encompassed within it, an incorrect calculation
> > occurs for dma_addressing_limited(), which prevents the nvme device
> > dma mapping in the checking path of phys_to_dma().
> 
> Nit: the subject and this description aren't very clear - the key point here is the
> unusual case that the range map covers right up to the top of system RAM, but
> leaves a hole somewhere lower down. There's no issue with the more typical
> case where some RAM exists above the top of the range map, since
> bus_dma_limit will capture that and work as expected.
> 
Ok, how about 
dma-mapping: fix dma_addressing_limited if dma_range_map can't cover all system RAM

> > E.g. On an Armv8 Ampere server, the dsdt ACPI table is:
> >   Method (_DMA, 0, Serialized)  // _DMA: Direct Memory Access
> >              {
> >                  Name (RBUF, ResourceTemplate ()
> >                  {
> >                      QWordMemory (ResourceConsumer, PosDecode,
> > MinFixed, MaxFixed, Cacheable, ReadWrite,
> >                          0x0000000000000000, // Granularity
> >                          0x0000000000000000, // Range Minimum
> >                          0x00000000FFFFFFFF, // Range Maximum
> >                          0x0000000000000000, // Translation Offset
> >                          0x0000000100000000, // Length
> >                          ,, , AddressRangeMemory, TypeStatic)
> >                      QWordMemory (ResourceConsumer, PosDecode,
> > MinFixed, MaxFixed, Cacheable, ReadWrite,
> >                          0x0000000000000000, // Granularity
> >                          0x0000006010200000, // Range Minimum
> >                          0x000000602FFFFFFF, // Range Maximum
> >                          0x0000000000000000, // Translation Offset
> >                          0x000000001FE00000, // Length
> >                          ,, , AddressRangeMemory, TypeStatic)
> >                      QWordMemory (ResourceConsumer, PosDecode,
> > MinFixed, MaxFixed, Cacheable, ReadWrite,
> >                          0x0000000000000000, // Granularity
> >                          0x00000060F0000000, // Range Minimum
> >                          0x00000060FFFFFFFF, // Range Maximum
> >                          0x0000000000000000, // Translation Offset
> >                          0x0000000010000000, // Length
> >                          ,, , AddressRangeMemory, TypeStatic)
> >                      QWordMemory (ResourceConsumer, PosDecode,
> > MinFixed, MaxFixed, Cacheable, ReadWrite,
> >                          0x0000000000000000, // Granularity
> >                          0x0000007000000000, // Range Minimum
> >                          0x000003FFFFFFFFFF, // Range Maximum
> >                          0x0000000000000000, // Translation Offset
> >                          0x0000039000000000, // Length
> >                          ,, , AddressRangeMemory, TypeStatic)
> >                  })
> >
> > But the System RAM ranges are:
> > cat /proc/iomem |grep -i ram
> > 90000000-91ffffff : System RAM
> > 92900000-fffbffff : System RAM
> > 880000000-fffffffff : System RAM
> > 8800000000-bff5990fff : System RAM
> > bff59d0000-bff5a4ffff : System RAM
> > bff8000000-bfffffffff : System RAM
> > So some RAM ranges are out of dma_range_map.
> >
> > Fixes it by checking whether each of the system RAM resources can be
> > properly encompassed within the dma_range_map.
> >
> > Signed-off-by: Jia He <justin.he@arm.com>
> > ---
> >   include/linux/dma-mapping.h |  8 +++++--
> >   kernel/dma/mapping.c        | 45
> +++++++++++++++++++++++++++++++++++++
> >   2 files changed, 51 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> > index f0ccca16a0ac..d9d1c67c8579 100644
> > --- a/include/linux/dma-mapping.h
> > +++ b/include/linux/dma-mapping.h
> > @@ -144,6 +144,7 @@ bool dma_pci_p2pdma_supported(struct device
> *dev);
> >   int dma_set_mask(struct device *dev, u64 mask);
> >   int dma_set_coherent_mask(struct device *dev, u64 mask);
> >   u64 dma_get_required_mask(struct device *dev);
> > +bool all_ram_in_dma_range_map(struct device *dev);
> >   size_t dma_max_mapping_size(struct device *dev);
> >   size_t dma_opt_mapping_size(struct device *dev);
> >   bool dma_need_sync(struct device *dev, dma_addr_t dma_addr); @@
> > -475,8 +476,11 @@ static inline int dma_coerce_mask_and_coherent(struct
> device *dev, u64 mask)
> >    */
> >   static inline bool dma_addressing_limited(struct device *dev)
> >   {
> > -	return min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
> > -			    dma_get_required_mask(dev);
> > +	if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
> > +						dma_get_required_mask(dev))
> 
> Nit: indentation
> 
> > +		return true;
> > +
> > +	return !all_ram_in_dma_range_map(dev);
> >   }
> >
> >   static inline unsigned int dma_get_max_seg_size(struct device *dev)
> > diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index
> > e323ca48f7f2..ab407deb81b8 100644
> > --- a/kernel/dma/mapping.c
> > +++ b/kernel/dma/mapping.c
> > @@ -14,6 +14,7 @@
> >   #include <linux/of_device.h>
> >   #include <linux/slab.h>
> >   #include <linux/vmalloc.h>
> > +#include <linux/dma-direct.h>
> 
> Nit: please keep the includes sorted alphabetically, however I do wonder
> whether this whole thing shouldn't belong in dma-direct anyway.
The dma-direct.h is for including struct bus_dma_region only.
Maybe I need to move struct bus_dma_region to a proper header file?

> 
> >   #include "debug.h"
> >   #include "direct.h"
> >
> > @@ -819,6 +820,50 @@ size_t dma_opt_mapping_size(struct device *dev)
> >   }
> >   EXPORT_SYMBOL_GPL(dma_opt_mapping_size);
> >
> > +/*
> > + * To check whether all ram resource ranges are mapped in dma range
> > +map
> > + * Returns 0 when continuous check is needed
> > + * Returns 1 if there is some ram range can't be mapped to
> > +dma_range_map  */ static int check_ram_in_range_map(unsigned long
> > +start_pfn,
> > +				  unsigned long nr_pages, void *data) {
> > +	phys_addr_t end_paddr = (start_pfn + nr_pages) << PAGE_SHIFT;
> 
> This could still wrap to 0 on 32-bit. I think the robust thing to do is either spray
> some extra -1s and +1s around to make all the "end" values inclusive limits, or
> maybe just do everything in units of pages rather than bytes (i.e. use
> PFN_DOWN() on the bus_dma_region entry values).
> 
Ok, let me try the latter one, which looks easier to me.

> > +	phys_addr_t start_paddr = start_pfn << PAGE_SHIFT;
> > +	struct device *dev = (struct device *)data;
> > +	struct bus_dma_region *region = NULL;
> > +	const struct bus_dma_region *m;
> > +
> > +	while (start_paddr < end_paddr) {
> > +		// find region containing start_paddr
> 
> Nit: inconsistent comment style (although it's not a particularly valuable
> comment anyway, IMO the loop itself is clear enough).
> 
Sure, let me remove it.


--
Cheers,
Justin (Jia He)